Large amplitude driving of a persistent current qubit
Author(s)Berns, David Marc
Massachusetts Institute of Technology. Dept. of Physics.
Terry P. Orlando and Mildred S. Dresselhaus.
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In this thesis, the persistent current qubit in the presence of large amplitude microwave radiation is studied. Three main results are presented in this work. A new coherent quasi classical regime has been observed, where coherent quantum dynamics persist even while transitions between energy levels are caused by many photon modes simultaneously. A new theoretical treatment of this regime has been developed, and remarkable agreement between theory and experiment is observed. Also presented is a novel application of strong driving, where unwanted excited state population is cooled to the ground state by utilizing a second avoided crossing. This method of cooling, via a third, ancillary qubit level, is analogous to atomic sideband cooling. Cooling from 400mK to 3mK has been achieved. Finally, a new type of spectroscopy is presented, where an entire manifold of quantum levels is characterized with a single driving frequency, by studying the amplitude dependence of the qubit's behavior. Characterization of energy level spacings reaching 120GHz is achieved with radiation on the order of 0.1GHz.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.Includes bibliographical references (p. 181-190).
DepartmentMassachusetts Institute of Technology. Dept. of Physics.
Massachusetts Institute of Technology